/Engine/Source/Runtime/Experimental/Chaos/Public/Chaos/PBDRigidClustering.h
This function is a bit more versatile than the name suggests. This function can either be used to update the cluster properties incrementally or entirely rebuild the properties all over again. This all depends on whether the input children is either 1) the new children or 2) all the children as well as what those initial properties are set to.
void UpdateClusterParticlePropertiesFromChildren ( [FPBDRigidClusteredParticleHandle](API\Runtime\Chaos\Chaos\FPBDRigidClusteredParticleHandle) * Cluster, const [FRigidHandleArray](API\Runtime\Chaos\Chaos\FRigidClustering\FRigidHandleArray) & Children, const [TMap](API\Runtime\Core\Containers\TMap)< [FPBDRigidParticleHandle](API\Runtime\Chaos\Chaos\FPBDRigidParticleHandle) *, [FPBDRigidParticleHandle](API\Runtime\Chaos\Chaos\FPBDRigidParticleHandle) * > & ChildToParentMap )